Production of butinediol



Patented Nov. 1, 1949 2,487,006 raonuc'rrou or BUTINEDIOL Joseph Frederic Walker, Westfield, N. J and Thomas E. Londergan, Niagara Falls, N. Y., asslgnors to E. I. du Pont de Neinours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 4, 1947, Serial No. 778.021

4 Claims. 1

This invention relates to an improved process for the production of 2-butinediol-1,4.

This application is a continuation-in-part of our copendir'ig application Serial No. 556,474, filed September 29, 1944, and now abandoned.

The recently granted patent to Reppe et al., U. 8. Patent No. 2,232,867 discloses a process for the production of 2-butinediol-1,4 by reacting an aqueous solution of formaldehyde with acetylene in the presence of a metal acetylide catalyst selected from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide. By the process of said patent, it is impossible to obtain a satisfactory yield of the buti'nediol within a reasonable period of time unless the process is operated at superatmospheric pressure. n the other hand, when super-atmospheric pressures are used, as suggested in the patent, the process is dangerous by reason of the explosion hazard of acetylene'under pressure. The process of the above-said patent is also subject to the objection that the 2-butinediol-l,4 produced contains, as an impurity, small amounts of propargyl alcohol.

It is an object of this invention to provide a process for the production of 2-butinediol-l,4 which will have an excellent yield and may be carried out in a minimum period of time at atmospheric pressure.

It is another object of this invention to provide a process for the production of 2-butinedio1-l,4 which will have an excellent yield and may be carried out in a minimum period of time without objectionable explosion hazard.

It is another object of this invention to provide a process for the production of 2-butinediol-L4 which is substantially free from propargyl alcohol.

Other objects of the invention will appear hereinafter.

The objects may be accomplished, in general, by reacting a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in a liquid reaction medium, taken from the group consisting of acetonyl acetone and cyclohexanone, containing not to exceed 5% free water. The reaction is carried out in the presence of a metal acetylide taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide, and at a temperature between 60 C. and 150 C.

The above-said polyoxymethylene glycol includes paraformaldehyde, which Staudinger has defined as a mixture of polyoxymethylene glycols containing between eight and one hundred formaldehyde units. as well as similar polymers of formaldehyde which may have a more uniform degree of polymerization. It has been found, in accordance with this invention, that commercial formaldehyde solutions or similar aqueous solutions of formaldehyde cannot be reacted with acetylene at atmospheric pressure to produce a good yield of the butinediol unless the reaction is carried out for a long period of time (a period of two. or more days). By the use of paraformaldehyde, or similar polyoxymethylene glycol, in a liquid reaction medium, taken from the group consisting of acetonyl acetone and cyclohexanone, containing not to exceed 5% free water, a good yield can be obtained at atmospheric pressure in a period of two to six hours. Not only is the paraformaldehyde more reactive than formaldehyde but free water in larger quantities than about 5%, as well as alcohol and hydrocarbons, in the reactionmedium, have a decided inhibiting effect on the reaction. On the other hand, it has been found that 'polyoxymethylene glycols having more than one hundred formaldehyde units per molecule, 1. e., formaldehyde polymers known as alpha-polyoxymethylene. are not suitable for the production of 2-butinediol-1,4 since they are not sufiiciently reactive.

Paraformaldehyde is readily produced by the evaporation of a formaldehyde solution, and the process of this invention may be carried out with paraformaldehyde produced in situ in the reaction medium by passing an aqueous formaldehyde solution into the hot reaction medium through which an excess of acetylene is being swept so as to carry oil excess water. This procedure must be so controlled that a concentration of more than 5% free water will never be present in the reaction mixture. Paraformaldehyde can also be produced in situ by passing formaldehyde gas into a substantially non-aqueous reaction mixture. Aqueous formaldehyde solutions such as commonly marketed, or monomeric formaldehyde gas, as such, are not satisfactory for use in carrying out the present invention.

Acetylene usually contains a considerable proportion of water; It may, therefore, be necessary to first dry the acetylene before passing the same into the reaction mixture to prevent building up a concentration of more than 5% free water.

In accordance with the present invention, the reaction between the acetylene and the polyoxymethylene glycol is carried out in a liquid reaction medium taken from the group consisting of acetonyl acetone and cyclohexanone. As above stated, water, alcohol, and hydrocarbons have now been found to inhibit the reaction. The liquid reaction medium employed must, therefore, contain less than 5% free water or like reactioninhibiting liquid. The amount of the liquid reaction medium employed is not critical. cient amount should, of course, be used to maintain the reaction mass in a liquid, dissolved or slurry, form. Ina batch type process the liquid reaction medium is preferably employed in an amount between three and twenty times the weight of the polyoxymethylene glycol present in the reaction mass. In a continuous type proc ess, the butinediol may be continuously removed by distillation of the reaction mass, and the reaction medium recycled. The 2-butinediol-1,4 produced by the reaction will, unless removed, accumulate in the reaction mass. It has now been found that small amounts of the butinediol will not interfere with the reaction; however, if it is allowed to accumulate until it exceeds about 50%, based on the combined weight of the butinediol and the liquid reaction medium, it will materially interfere with the production of good yields. It is, therefore, preferred that the concentration of the 'butinediol product in the reaction mass be not allowed to exceed 50% based on the combined weight of the butinediol and the liquid reaction medium employed. This may be readily accomplished by discontinuing the reaction or by adding additional liquid reaction medium in a batch type process, or by continuous removal of the butinediol from the reaction medium by distillation of the reaction mass and recycling of the 1 reaction medium, or by continuous addition of reaction medium in a continuous type process.

The metal acetylide catalyst, i. e., copper acetylide, silver acetylide, gold acetylide or mercury acetylide, or any mixture or combination thereof, may be prepared from aqueous metal salt solutions as disclosed in the above-said patent to Reppe et al. The metal acetylide should be contained on a catalyst support such as fuller's earth, infusorial earth, activated carbon, silica gel, or the like. The preferred metal acetylide catalyst material for use in accordance with this invention is one produced by mixing particles of a catalyst support having a size not to exceed 300-mesh with an aqueous solution of a metal salt and precipitating the metal acetylide on the particles of catalyst support by passing acetylene through the said mixture. The quantity of metal acetylide precipitated on the particles of support should not exceed by Weight, of the final dry catalyst. This particular catalyst and the method of producing the same is the subject of our copending patent application Serial No. 561,150, filed October 30, 1944. The amount of catalyst present in the reaction mass may be varied between wide limits, for example, the presence of 1% to based on the weight of the polyoxymethylene glycol present, will catalyze the reaction.

The reaction between the polyoxymethylene glycol and the acetylene will take place at atmospheric pressure at any temperature between C. and 150 C. In order that good commercial yields be obtained in minimum time and in order to maintain the process under safe conditions of operation, it is preferred to carry out the reaction at a temperature between 115 C. and 125 C.

The followin detailed examples are given to illustrate certain preferred methods for carrying out the present invention, it being understood, of course, that the precise details set forth 4 in these examples are to be taken as illustrative and not limitative of the invention.

Example I acetylene absorption. Additional paraformaldehyde was added after one-half mol of acetylene had been absorbed and addition was continued until a total of 315 grams or equivalent to ten gram-molecular weights of CHzO as paraformaldehyde had been added. When acetylene absorption was complete, the reaction mixture was filtered and the catalyst washed with cyclohexanone, these washings being added to the filtrate. The 2-butinediol-1,4 was isolated from the illtered reaction mixture by vacuum distillation, distilling at 120 C. to 145 C. at 7 mm. On redistillation, a substantially pure product, boiling at 130 C. to 135 C. at 7 mm., was secured. A yield of 352 grams or 82% theoretical was obtained. The butinediol produced by the above reaction was free from propargyl alcohol.

Example II To 400 grams of acetonyl acetone were added 16 grams of copper acetylide (on grams, 300- mesh or finer, active carbon) and 63 grams of paraformaldehyde. The mixture was then heated to 125 C. and acetylene was bubbled through it with constant agitation at atmospheric pressure. Approximately 70% of the theoretical acetylene was absorbed in two hours and the reaction was substantially complete in three hours. The reaction mixture was filtered, the catalyst being washed with a small quantity of acetonyl acetone and the 2-butinediol-1,4 recovered from the filtrate by vacuum distillation. The yield was approximately 82 grams or theoretical.

The reaction product was substantially free from propargyl alcohol.

Example III Two mols of formaldehyde in the form of 60 grams of alpha-polyoxymethylene containing 99.9% formaldehyde were added to 400 grams of acetonyl acetone containing 16 grams of copper acetylide on 80 grams of powdered, substantially pure, neutral activated carbon. Acetylene was passed through the resultant mixture with agitation for one hour at C. with absorption of only 2.5 liters; the temperature was then raised to C., but only 1.3 liters were absorbed in one-half hour: This is only 25% to 27% of the quantity of acetylene which would be absorbed by paraformaldehyde under similar circumstances. This example illustrates that alpha-polyoxymethylene is not sufliciently reactive to be a satisfactory reactant for use in accordance with the present invention.

Example IV An approximately equimolar mixture of acetylene and monomeric formaldehyde gas containing about one moi each of formaldehyde and acetylene was bubbled through 300 grams of acetonyl acetone, containing eight grams of copper acetylide on 40 grams of substantia-ily pure, neutral activated carbon, with agitation at 100 C. in the course of two and one-quarter hours. In this time, only about 13% of the acetylene was absorbed indicating that only 25% of the theoretical quantity had reacted. At the same time, all of the formaldehyde was absorbed and held by the reaction mixture. Acetylene was then passed through the mixture for four and one-quarter hours, in which time about 65% of the theoretical amount reacted, making a total of 90% theoretical for one moi formaldehyde. I

These results indicate that during the first two and one-quarter hours, about 75% of the formaldehyde either polymerized or formed a complex with the reaction medium since monomer could not be absorbed as such at 100 C. The rate of acetylene absorption was faster in the last part of the experiment indicating that the reaction proceeded more rapidly with polymer or complex than with monomeric formaldehyde.

In all of the above examples, the acetylene was passed into the solvent containing formaldehyde, or formaldehyde polymer, at atmospheric pressure.

. By the. process of this invention, 2'-butinediol-1,4 is readily produced at atmospheric pressure and, therefore, without the menace of explosion such as is present in the handling or maintaining of the acetylene at pressures above atmospheric. The reaction takes place rapidly with excellent yields without the production of propargyl alcohol, and the butinediol can be readily isolated from the solvents employed since it is substantially free from water.

Throughout the specification and claims, proportions and percentages refer to proportions and percentages by weight unless otherwise specified.

Since .it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of this invention, it is to be understoodthat the invention is not to be limited to the abovesaid details except as set forth in the appended claims.

What is claimed is:

1. A process for the production of 2-butinedial-1,4 which comprises reacting, at a temperature between 60 C. and 150 C... a polyoxymethylene glycol containing between eight and one hundred formaldehyde units. per molecule with acetylene in a liquid reaction medium, taken from the group consisting of acetonyl acetone and cyclohexanone, which does not contain to exceed 5%, by weight, free water and which is present in sufficient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acet ylide, silver acetylide, gold acetylide, and mercury I acetylide.

2. A process for the production of 2-butinediol-1,4 which comprises reacting, at a temperature between C. and C., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in a liquid reaction medium, taken from the group consisting of acetonyl acetone and cyclohexanone, which does not contain to exceed 5%, by weight, free water and which is present in sufncien't amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury which is present in suiflcient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide.

4. A process for the production of 2-butinediol-1,4 which comprisesreacting, at a temperature between 60 C. and 0., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in cyclohexanone which does not contain to exceed 5%, by weight, free water and which is present in sufficient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide.

JOSEPH FREDERIC WALKER. THOMAS E. LONDERGAN.

REFERENCES CITED The following references are of record in the flle of this patent:

v UNITED STATES PATENTS Number 

